Used turn VD function

The turns VD function is used for assignment with ICA of all opened turns whose nodes include a Node impedance calculation (ICA).

where

tcur	Turn attribute corresponds to tCur of the turn-specific VD function, including the VD function parameters. Attribute tCur-PrTSys for assignment with ICA contains the value calculated at the end of the assignment with ICA.
A and B	Attributes of the respective turns. The attributes Final A for assignment with ICA and Final B for assignment with ICA include the values calculated at the end of the assignment with ICA.
q	Turn volume in subordinate assignment (without spillback congestion)
t0	Turn attribute Attribute Final t0 for assignment with ICA contains the value calculated at the end of the assignment with ICA.
cap	Turn attribute that corresponds to smoothed capacity in the assignment with ICA. Attribute Final capacity for assignment with ICA contains the value calculated at the end of the assignment with ICA.
Δq	Turn attribute calculated as the difference between demand volume and volume. Suppressed volume refers to the part of the volume that, according to blocking back calculation, is held back at bottlenecks upstream from the turn and so does not reach it. Attribute Suppressed volume upstream in assignment with ICA contains the value calculated at the end of the assignment with ICA.

During the assignment, the factors A and B are updated with each ICA impedance calculation per turn. You can find the values of the last iteration in the turn attributes Final A for assignment with ICA and Final B for assignment with ICA. The following data is also saved to turn attributes: t0 values (Final t0 for assignment with ICA), the capacity (Final capacity for assignment with ICA), and the difference between demand volume and current volume (Suppressed volume in assignment with ICA).

Note: An exception in the estimate of the turn VD function parameters form nodes with the control type Roundabout, which are calculated with the impedance model TRL/Kimber. The estimate of the parameters is approach-based here, the estimated values are thus identical for all turns of an approach and also the resulting wait times.